I am incredibly upset by this, I have spent over a week on this project to have the app just delete most of it. I have Sketch version 4.0.2 on iPhone 6S and was just working on a layer when the undo function started acting up (I would draw two separate lines and instead of undoing one, it would undo both). This happened a few times consecutively but didn't really bother me until I tried to undo something and almost everything in that layer was deleted. No matter how far back I go with the undo function, the work is still not there. I have no idea what to do now. The app had worked perfectly until this point, this is such a letdown.

My question is, what caused this? And is there any chance of recovering this work?

I'm really sorry about what happened with your work. This is not a bug I've ever heard reported, so it's really difficult to determine exactly what happened.

Can you email me through the in-app feedback.... for a couple of reasons: There is device data in those emails that might be helpful to our engineers, and if there is a way to recover your work (I'm not sure whether it's possible or not), we will need you to give us access to your account.